b'CRCA Policy CRCA Policy Statement on Wind Loads and Responsibility for Commercial nNovember2023,the1. DesignWindPressure(q):resistanceofmembrane-roofingsys-I Canadian Roofing ContractorsThisiscalculatedusinglocaltemsis a test method that simulates Roof Design Association (CRCA) released aclimate data, building height,real-world wind conditions.pivotal document: Test Standardexposureandthesurround- 1. What it does: The test mim-CSAA123.21Applicationinglandscape. ics actual wind conditions us-Policy. This policy guide addresses2.Pressure Coefficients (Cp):ing dynamic load cycles.both roofing contractors and theDifferentzones(corner,pe- 2. Whatitcovers:Thisstan-design community. rimeter, field) experience dif- dard applies to a wide range of Youcanfindthisinformativeferent uplift forces and thesemembrane roof systemsad-documentatcrcaacec.ca/articles/ coefficientshelpquantify test-standard-csa-12321-applicathosevariations. hered,mechanicallyattached tion-policy. 3.Load Combinations: Design- andpartiallyattached.Itap-Thisdocumentbuildsontheersconsiderhowwindinter- pliestoconventionallyinsu-CRCA policy, exploring: acts with dead loads, live loads,lated and uninsulated systems.1. Wind loads and roof designsnow loads, and seismic forces3. What it doesnt cover: Pro-Think Safe, intricacies; to create a resilient structure. tected or ballasted systems and 4.Documentation:Windloadliquid-applied membranes.Work Safe, 2.CSA A123.21s role in windcalculationsmustbeclearly 4. Whosresponsible:Manu-since 1988 uplift testing; and presentedinstructuraldraw-3.Designresponsibilitiesforfacturers test their membrane ingsandincludedinpermit Top-Line Roofing & Sheet-Metal Inc. specializescommercial roofing systems. applications. roofingsystemsaccordingto in the installation, repair, and maintenance ofThe NBCC sets a clear standard:CSA A123.21.industrial roofs throughout Southern Ontario.Wind Loads andthe design wind uplift loads (calcu- 5.Theresults:DetailedlabOUR SERVICES:Commercial roofing Re-roofing RoofDesign lated through Part 4) must be lessreports break down the roof-Roof maintenance Skylight installation TheNationalBuildingCodethan the wind uplift resistance dem- ingsystemcomponents,and Roof inspection,Sheet metal flashing,of Canada (NBCC) classifies windonstrated through testing that com- detail how each piece should evaluation & report fabrication & installation plies with CSA A123.21. beinstalled.Historical restoration Retro-fit curb installation loadsasstructuralloads,giving Emergency roof repairs themprominenceinDivisionB,6. Whyitmatters: This stan-Part 4 (Structural Design) and Di- CSA A123.21: Settingdard is referenced in Sentence (905) 602-0760 vision C, Part 2. This classificationthe Standard for Wind- 5.2.2.2.(4)ofDivisionBin 1325 Fewster Dr underscoresthecriticalnatureofResistant Roofs theNationalBuildingCode Mississauga, ONL4W 1A2toplineroofing.ca wind in building design. Key ele- The CSA A123.21Standard testofCanadaandisabuilding ments include: method for the dynamic wind upliftcode requirement.12ONTARIO ROOFING NEWSISSUE 4 2025/26 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'